I exported my game for HTML5. The game runs perfectly fine on the Godot editor, but it crashes if I change the initial scene, even if the scene is completely blank save for a Control. Here's what I see on the developer console.
Godot Engine v3.4.stable.mono.official.206ba70f4 - https://godotengine.org tmp_js_export.js:347:16
OpenGL ES 2.0 Renderer: ANGLE (Intel(R) HD Graphics 400 Direct3D11 vs_5_0 ps_5_0, D3D11-27.20.100.9664) tmp_js_export.js:347:16
OpenGL ES Batching: ON tmp_js_export.js:347:16
tmp_js_export.js:347:16
ERROR: Mono: Core API hash mismatch. tmp_js_export.js:362:18
at: _init_godot_api_hashes (modules/mono/mono_gd/gd_mono.cpp:490) - Mono: Core API hash mismatch. tmp_js_export.js:362:18
Mono: Config attempting to parse: '/root/mono-installs/wasm-runtime-release/etc/mono/config'. tmp_js_export.js:347:16
Mono: Config attempting to parse: '/home/web_user/.mono/config'. tmp_js_export.js:347:16
ERROR: Cannot open file 'res://Init.tscn'. tmp_js_export.js:362:18
at: load_interactive (scene/resources/resource_format_text.cpp:1183) - Condition "err != OK" is true. Returned: Ref<ResourceInteractiveLoader>() tmp_js_export.js:362:18
ERROR: Failed loading resource: res://Init.tscn. Make sure resources have been imported by opening the project in the editor at least once. tmp_js_export.js:362:18
at: _load (core/io/resource_loader.cpp:271) - Condition "found" is true. Returned: RES() tmp_js_export.js:362:18
ERROR: Failed loading scene: res://Init.tscn tmp_js_export.js:362:18
at: start (main/main.cpp:1998) - Condition "!scene" is true. Returned: false tmp_js_export.js:362:18
exception thrown: RuntimeError: indirect call to null,godot_js_main(int, char**)@:wasm-function[15324]:0x2ca1c5
main@:wasm-function[31565]:0x73169e
Godot/Module._main@http://localhost:8060/tmp_js_export.js:9:403120
callMain@http://localhost:8060/tmp_js_export.js:9:415259
SafeEngine/start/Engine</</<@http://localhost:8060/tmp_js_export.js:694:17
SafeEngine/start/Engine</<@http://localhost:8060/tmp_js_export.js:689:14
tmp_js_export.js:362:18
indirect call to null tmp_js_export.html:213:13